Lack of Buyer urgency — especially amongst the folks coming through weekend open houses (assuming that they really are Buyers).
There’s only one (at least that I know): other, serious Buyer interest in a particular home.
Which in turn is a function of the home’s price, condition, and — yup! — good marketing (including staging).
P.S.: Thankfully (for Realtors), not all Buyers lack motivation.
That includes relocation Buyers, renters with terminating leases, growing families, etc.